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  1. I have an AVI file that is recorded with a screencap tool. The file plays perfectly in both VLC and Windows Media Player, but when I open it in VirtualDubMod, the video is skewed to the left - and also it's in black and white:

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    The odd thing is that when I play the video in VirtualDobMod, it plays fine (and in colour) - but when I trim the video and save it (in Full Processing Mode), the output file is skewed

    Any idea what is going on? I haven't applied any filters to the video stream.
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  2. vanished El Heggunte's Avatar
    Join Date: Jun 2009
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    Probably a frame-dimension issue with the VfW version of the codec.

    A MediaInfo report about the file would be heplful.
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  3. Originally Posted by El Heggunte View Post
    Probably a frame-dimension issue with the VfW version of the codec.

    A MediaInfo report about the file would be heplful.
    Like this?

    Code:
    General
    Complete name                            : Arven 1-5.avi
    Format                                   : AVI
    Format/Info                              : Audio Video Interleave
    Format profile                           : OpenDML
    File size                                : 1.19 GiB
    Duration                                 : 1h 3mn
    Overall bit rate                         : 2 692 Kbps
    Writing application                      : Lavf52.23.1
    
    Video
    ID                                       : 0
    Format                                   : MPEG-4 Visual
    Codec ID                                 : MP42
    Codec ID/Info                            : Microsoft MPEG-4 v2 (pre-standard)
    Codec ID/Hint                            : Microsoft
    Duration                                 : 1h 3mn
    Bit rate                                 : 2 584 Kbps
    Width                                    : 938 pixels
    Height                                   : 524 pixels
    Display aspect ratio                     : 16:9
    Frame rate                               : 15.000 fps
    Compression mode                         : Lossy
    Bits/(Pixel*Frame)                       : 0.350
    Stream size                              : 1.14 GiB (96%)
    
    Audio
    ID                                       : 1
    Format                                   : MPEG Audio
    Format version                           : Version 1
    Format profile                           : Layer 3
    Codec ID                                 : 55
    Codec ID/Hint                            : MP3
    Duration                                 : 1h 3mn
    Bit rate mode                            : Constant
    Bit rate                                 : 96.0 Kbps
    Channel(s)                               : 1 channel
    Sampling rate                            : 44.1 KHz
    Compression mode                         : Lossy
    Stream size                              : 43.5 MiB (4%)
    Alignment                                : Aligned on interleaves
    Interleave, duration                     : 26 ms (0.39 video frame)
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  4. If the dimensions of your image are accurate (938x524), I'd guess it's a mod2 thing. It's something to do with a Windows API I don't really understand, but the upshot of it is, some programs don't like mod2 YUV video.
    Traditionally all video was mod16 (the width and height are divisible by 16). These days it doesn't matter much, but mod4 widths are still safer. The height can be mod2. Well at least for h264. For Xvid encoding it might still be safer to at least stick to a mod8 width and height, just for hardware player compatibility.

    If you're just wanting to re-encode while trimming it, the easiest way might be to use a different program. Handbrake would be nice and easy to use, but it'll only encode with the x264 encoder. MeGUI can output Xvid AVI but it's harder to use. If I'm correct, lots of programs should be able to open and re-encode it, just not VirtualDub(Mod). Although..... if you happen to have ffdshow installed and it happens to be doing the decoding, you should be able to use it's crop or resize filter to resize the video to a mod4 width as it's being decoded.
    Last edited by hello_hello; 23rd Jan 2014 at 06:42.
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  5. Yes, the VFW MP42 decoder doesn't like the mod2 frame width. Try using a different MP42 decoder. Sometimes you can patch the AVI header to work around this but you have to know what you're doing.
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  6. Originally Posted by jagabo View Post
    Yes, the VFW MP42 decoder doesn't like the mod2 frame width. Try using a different MP42 decoder. Sometimes you can patch the AVI header to work around this but you have to know what you're doing.
    Thanks for your suggestions - but I managed to trim the file by switching to "Direct stream copy" mode. The preview video is still skewed (both the original and the output preview), but the saved output file is ok.
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  7. Originally Posted by Pokersut View Post
    the saved output file is ok.
    Until you try to play it on a future device that doesn't like the mod2 frame width.
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